Abstract: The peptide was separated through ultrafiltration from sika deer antler base. The major factors such as pressure, operation time, and material-liquid ratio were investigated to evaluate the effect on infiltration flux.Based on one-factor-at-atime method, Box-Behnken response surface methodology ( RSM) was taken to optimize the key factors that affect the effect of the sika deer antler peptide ultrafiltration. The optimal separation condition was 1.44% of material-liquid ratio, 0.13 MPa of pressure, and 60 min of operation time.Under this condition, the infiltration flux could be reached 1.72 L/m2·h, peptide content in separated samples was 45.2%, better purification effect was achieved.